JP2022077389A - Biological information acquisition device - Google Patents

Abstract

To provide a biological information detection device capable of acquiring a stable detection result.SOLUTION: A biological information acquisition device includes: a base material part installed on a handle of a movable body; first electrodes 20LA, 20RA disposed on the base material part, and arranged in positions to be a front side when viewed from a side of a driver who grips the handle; second electrodes 20LB, 20RB disposed on the base material part, and arranged in positions to be a depth side when viewed from a side of the driver who grips the handle; and a biological information detection part 301 for detecting the biological information of the driver who grips the handle via at least any of the first electrodes and the second electrodes. The biological information detection part switches a function related to the detection of the biological information of the first electrodes and the second electrodes according to a situation related to the detection of the biological information.SELECTED DRAWING: Figure 4

Description

The present invention relates to a biological information acquisition device.

Currently, left and right electrodes are installed on the left and right grips of the steering wheel of the vehicle, respectively, so that the driver can measure the electrocardiographic waveform of the driver simply by grasping the steering wheel of the vehicle. Biometric information measuring devices are known (see, for example, Patent Document 1). Such a biological information measuring device includes a potential difference detection circuit that detects a potential difference between a left electrode and a right electrode, and a data processing unit that detects an electrocardiogram signal indicating an electrocardiographic waveform of a driver and a heart rate based on the potential difference. Is provided.

Japanese Unexamined Patent Publication No. 2017-217221

Each of the left electrode and the right electrode is composed of a sheet-shaped rubber electrode provided on the surface of a cover that can be attached to and detached from the handle. The driver of the vehicle always holds the steering wheel while driving, and the rubber electrode is always in contact with the driver's palm. Therefore, the rubber electrode may be worn and the characteristics of the electrode may be changed.

Further, each of the left electrode and the right electrode is composed of a pair of split electrodes. One of the pair of split electrodes has the function of an active electrode and the other has a function of a neutral electrode. When measuring biometric information, the driver's skin must be in contact with the active electrodes. On the other hand, the neutral electrode is an electrode that provides a reference point for electric potential.

The mode of gripping the steering wheel by the driver may differ depending on the driving situation and the type of vehicle. Therefore, if the arrangement of the active electrode and the neutral electrode is fixed, it may not be possible to stably acquire biometric information.

The present invention has been made in view of the above points, and one of the objects of the present invention is to provide a biological information detection device capable of obtaining stable detection results.

The invention according to claim 1 is a base material portion to be installed on a handle of a moving body, and a second base material portion provided on the base material portion and arranged at a position on the front side when viewed from the driver side for gripping the handle. One electrode, a second electrode provided on the base material portion and arranged at a position on the back side when viewed from the driver side holding the handle, and at least one of the first electrode or the second electrode. The biometric information detection unit comprises a biometric information detection unit that detects the biometric information of the driver holding the handle, and the biometric information detection unit relates to the detection of the biometric information of the first electrode and the second electrode. It is characterized in that the function is switched according to the situation related to the detection of the biological information.

It is a block diagram which shows the structure of the biological information acquisition system. It is a front view of the steering wheel cover and the sensor electrode seen from the driver side. It is a front view of the steering wheel cover and the sensor electrode seen from the side opposite to the driver. It is sectional drawing in 3-3 line of FIG. 2A. It is a block diagram which shows the structure of the biological information detection unit 30. It is a graph which shows typically the change of RRI acquisition rate by vibration. It is a flowchart which shows the process routine of the electrode function switching process. It is a flowchart which shows the process routine of the electrode function switching process.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the description and the accompanying drawings in each of the following examples, substantially the same or equivalent parts are designated by the same reference numerals.

FIG. 1 is a system configuration diagram showing a configuration of a biological information acquisition system 100 mounted on a vehicle.

The biological information acquisition system 100 includes a handle cover 10 mounted on a steering wheel (also referred to as a steering wheel) of a vehicle, sensor electrodes 20L and 20R installed on the steering wheel cover 10, a biological information detection unit 30, and a display device 40.

The sensor electrode 20L is provided so as to be located in a region of the ring portion of the steering wheel that is gripped by the driver's left hand when the steering wheel cover 10 is attached to the steering wheel. The sensor electrode 20R is provided so as to be located in a region gripped by the driver's right hand. The sensor electrodes 20L and 20R are each connected to the biological information detection unit 30 via wiring (not shown).

The biological information detection unit 30 is provided so as to be located in a region corresponding to the spoke portion of the handle when the handle cover 10 is attached to the handle. The biological information detection unit 30 is a heart rate, an electrocardiogram, a respiratory rate, or a muscle from a potential difference generated between the sensor electrodes 20R and 20L, that is, an electric signal emitted from the body accompanying a biological phenomenon of a driver who comes into contact with the sensor electrode. It detects biological information such as an electrocardiogram and generates a biological information signal representing the detected biological information. Further, the biological information detection unit 30 generates a gripping signal indicating whether or not the driver is gripping the steering wheel based on the signals detected from the sensor electrodes 20R and 20L.

The biological information detection unit 30 has a wireless communication function for establishing wireless communication with the display device 40 by using Bluetooth (registered trademark) or the like. The biometric information detection unit 30 wirelessly transmits the biometric information signal and the gripping signal generated as described above to the display device 40.

The display device 40 has a display screen made of a liquid crystal panel or the like. The display device 40 is based on the biometric information signal received from the biometric information detection unit 30, information indicating the state of the driver's heart rate, electrocardiogram, respiratory rate, myocardiogram, etc., and secondary information that can be calculated from them. Display (drowsiness and fatigue) on the display screen. Further, when the gripping signal received from the biological information detection unit 30 indicates that the driver is not gripping the steering wheel, the display device 40 displays a text message on the display screen prompting the driver to grip the steering wheel. Display. Further, the display device 40 receives a request for notifying that the sensor electrodes 20L and 20R are deteriorated (electrode deterioration notification request) from the biological information detection unit 30, and the sensor electrodes 20L and 20R are deteriorated accordingly. Display a text message on the display screen to inform you that you are doing this.

Next, the configurations of the sensor electrodes 20L and 20R of this embodiment will be described with reference to FIGS. 2A, 2B and 3.

FIG. 2A is a front view of the steering wheel cover 10 and the sensor electrodes 20L and 20R as seen from the driver side (hereinafter, also referred to as the front side) when the steering wheel cover 10 is attached to the steering wheel. FIG. 2B is a front view of the handle cover 10 and the sensor electrodes 20L and 20R as seen from the side opposite to the driver (hereinafter, also referred to as the back side) when the handle cover 10 is attached to the handle. It should be noted that the illustration of the biological information detection unit 30 and the handle body is omitted here.

The steering wheel cover 10 is composed of a base material portion having a ring shape, and is configured to be mountable on the steering wheel of a vehicle.

The sensor electrode 20L is composed of a first electrode 20LA and a second electrode 20LB. Similarly, the sensor electrode 20R is composed of a first electrode 20RA and a second electrode 20RB. Each of the first electrode 20LA and the second electrode 20LB of the sensor electrode 20L, the first electrode 20RA of the sensor electrode 20R, and the second electrode 20RB is composed of a sheet-shaped rubber electrode, and the surface of the base material portion constituting the handle cover. It is provided in.

The sensor electrode 20L is a sensor electrode arranged on the left hand side of the driver when the steering wheel cover 10 is attached to the steering wheel of the vehicle. The first electrode 20LA of the sensor electrode 20L is arranged so as to be located on the front side when viewed from the driver when the handle cover 10 is attached. The second electrode 20LB of the sensor electrode 20L is arranged so as to be located on the back side when viewed from the driver when the handle cover 10 is attached.

Each of the first electrode 20LA and the second electrode 20LB of the sensor electrode 20L has a shape extending along the circumferential direction of the ring shape of the base material portion constituting the handle cover 10. In order to reduce slipperiness when the driver operates the handle, the width of the first electrode 20LA of the sensor electrode 20L (the width in the direction orthogonal to the stretching direction) is configured to be narrower than the width of the second electrode 20LB. .. That is, the first electrode 20LA of the sensor electrode 20L has an elongated shape than the second electrode 20LB.

FIG. 3 is a cross-sectional view taken along the line 3-3 (dashed line) of FIG. 2A. The handle cover 10 is composed of a tubular base material portion BP having an opening AP. The first electrode 20LA and the second electrode 20LB of the sensor electrode 20L are arranged at positions symmetrical with each other (that is, positions on opposite sides) of the surface of the base material portion BP.

Referring to FIGS. 2A and 2B again, the sensor electrode 20R is a sensor electrode arranged on the driver's right hand side when the steering wheel cover 10 is attached to the steering wheel of the vehicle. The first electrode 20RA of the sensor electrode 20R is arranged so as to be located on the front side when viewed from the driver when the handle cover 10 is attached. The second electrode 20RB of the sensor electrode 20R is arranged so as to be located on the back side when viewed from the driver when the handle cover 10 is attached.

Each of the first electrode 20RA and the second electrode 20RB of the sensor electrode 20R has a shape extending along the circumferential direction of the ring shape of the base material portion. The width of the first electrode 20RA of the sensor electrode 20R (the width in the direction orthogonal to the stretching direction) is narrower than the width of the second electrode 20RB. That is, the first electrode 20RA of the sensor electrode 20R has an elongated shape than the second electrode 20RB.

Further, a plurality of hole HLs are formed on the surfaces of the first electrode 20LA and the second electrode 20LB of the sensor electrode 20L, and the first electrode 20RA and the second electrode 20RB of the sensor electrode 20R. The plurality of hole portions HL are arranged along the circumferential direction of the ring shape of the base material portion constituting the handle cover 10.

The first electrode 20LA and the second electrode 20LB of the sensor electrode 20L are set so that one is an active electrode and the other is a neutral electrode. Similarly, the first electrode 20RA and the second electrode 20RB of the sensor electrode 20R are set so that one is an active electrode and the other is a neutral electrode.

The active electrode and the neutral electrode are functions of each sensor electrode related to detection of the bioelectric signal BS (hereinafter, simply referred to as electrode function). The active electrode has a function as a measuring electrode for acquiring an electric signal from the driver. The neutral electrode has a function as a reference electrode that provides a reference point for the potential in the potential measurement. Although it is possible to detect the bioelectric signal BS using only the active electrode, the neutral electrode is used to give the driver a potential that is in phase with the reference potential of the amplification amplifier (not shown) of the bioelectric signal BS. , The detection accuracy of biological information can be improved.

The biological information detection unit 30 of this embodiment switches the electrode functions of the first electrode and the second electrode (that is, which is the active electrode and which is the active electrode, depending on the detection result of the gripping signal, the deterioration state of each electrode, and the like. Switch whether it will be a neutral electrode).

In the first mode of electrode function setting, the first electrode 20LA of the sensor electrode 20L and the first electrode 20RA of the sensor electrode 20R are set to the neutral electrode. Further, the second electrode 20LB of the sensor electrode 20L and the second electrode 20RB of the sensor electrode 20R are set as active electrodes.

In the second mode of electrode function setting, the first electrode 20LA of the sensor electrode 20L and the first electrode 20RA of the sensor electrode 20R are set to the active electrodes. Further, the second electrode 20LB of the sensor electrode 20L and the second electrode 20RB of the sensor electrode 20R are set to the neutral electrode.

As described above, the sensor electrodes 20L and 20R are composed of sheet-shaped rubber electrodes, and in principle, the first electrode (20LA, 20RA) that the driver's palm contacts is the second electrode that the fingertips contact. It is easier to wear than (20LB, 20RB). Therefore, in order to prevent deterioration of the detection function of the biometric information signal due to wear of the rubber electrode (that is, deterioration of the electrode), the first electrode and the second electrode of the sensor electrodes 20L and 20R are in principle according to the first mode. The electrode function is set.

On the other hand, when the driver does not hold the steering wheel and puts his / her hand on the steering wheel to perform the driving operation, the functions of the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively, are It is set according to the second mode.

FIG. 4 is a block diagram showing an internal configuration of the biological information detection unit 30.

The biological information detection unit 30 includes a power supply circuit 300, a biological information detection circuit 301, a grip signal detection circuit 302, a memory 303, a transmission / reception circuit 304, an RRI calculation unit 305, an electrode state determination unit 306, and an electrode function switching circuit 307.

The power supply circuit 300 receives a battery voltage generated by a battery BT composed of a primary battery or a secondary battery, and generates a constant voltage power supply voltage based on the battery voltage. The power supply circuit 300 supplies the generated power supply voltage to the biometric information detection unit including the biometric information detection circuit 301 and the gripping signal detection circuit 302.

The biometric information detection circuit 301 acquires a signal based on the potential difference generated between the sensor electrodes 20L and 20R (hereinafter, referred to as bioelectric signal BS). Then, the biometric information detection circuit 301 detects an electrocardiogram as biometric information and a signal representing a heart rate (hereinafter referred to as biometric information signal BIS) based on the acquired bioelectric signal BS. The biological information detection circuit 301 supplies the biological information signal BIS to the transmission / reception circuit 304.

The gripping signal detection circuit 302 determines whether or not both hands of the driver of the vehicle are gripping the sensor electrodes 20L and 20R based on the current flowing between the sensor electrodes 20L and 20R. The gripping signal detection circuit 302 supplies a signal indicating a determination result (hereinafter, referred to as a gripping signal GS) to the control unit 400. The gripping signal detection circuit 302 generates a gripping signal GS for each of the driver's left hand side (sensor electrode 20L) and right hand side (sensor electrode 20R).

In this embodiment, "grasping" the sensor electrode means a state in which the driver's hand is in contact with both the first electrode and the second electrode of the sensor electrode. That is, when the driver's left hand is in contact with both the first electrode 20LA and the second electrode 20LB of the sensor electrode 20L, a grip signal GS indicating that the driver is gripping the sensor electrode 20L is generated. .. When the driver's left hand is in contact with only one of the first electrode 20LA and the second electrode 20LB, and is not in contact with either of them, it indicates that the driver is not holding the sensor electrode 20L. The grip signal GS is generated. Similarly, when the driver's right hand is in contact with both the first electrode 20RA and the second electrode 20RB of the sensor electrode 20R, a grip signal GS indicating that the driver is gripping the sensor electrode 20R is generated. To. When the driver's right hand is in contact with only one of the first electrode 20RA and the second electrode 20RB, and is not in contact with either of them, it indicates that the driver is not holding the sensor electrode 20R. The grip signal GS is generated.

The memory 303 is a non-volatile memory, and is used for registration information about the type of vehicle (vehicle type, model, vehicle name, etc.) in which the driver attaches the handle cover 10 to the handle, and driving for setting the function of each sensor electrode. It has a storage area for storing setting information for each individual (that is, which of the first mode and the second mode is set as the initial state).

The transmission / reception circuit 304 wirelessly transmits the above-mentioned biological information signal BIS and grip signal GS to the display device 40. Further, when the sensor electrodes 20L and 20R are determined to be deteriorated by the electrode state determination unit 306 and the electrode deterioration notification request is supplied from the control unit 400, the transmission / reception circuit 304 displays the electrode deterioration notification request. Wireless transmission to the device 40.

Further, the transmission / reception circuit 304 acquires information on acceleration (hereinafter, referred to as acceleration information) indicating vibration generated in the vehicle from an acceleration sensor (not shown) mounted on the vehicle. Alternatively, instead of acquiring the acceleration information via the transmission / reception circuit 304, an acceleration sensor may be provided in the biological information detection unit 30 itself to acquire the acceleration information. The acceleration information is used to determine the vibration generated in the vehicle and the acceleration in the front-rear direction of the vehicle in the electrode function switching process described later. Further, the transmission / reception circuit 304 acquires vehicle speed information of the vehicle from a vehicle speed sensor (not shown) mounted on the vehicle. The transmission / reception circuit 304 supplies the acquired acceleration information and vehicle speed information to the control unit 400.

The RRI calculation unit 305 calculates RRI (RR Interval) indicating the interval between heartbeats based on the biological information signal BIS detected by the biological information detection circuit 301. The RRI calculation unit 305 supplies the calculated RRI data to the control unit 400 and the electrode state determination unit 306.

The electrode state determination unit 306 determines the degree of deterioration of the sensor electrodes 20L and 20R based on the RRI data supplied from the RRI calculation unit 305. For example, the electrode state determination unit 306 determines the degree of deterioration of the sensor electrodes 20L and 20R based on the change in the RRI acquisition rate with respect to the vibration generated in the vehicle.

FIG. 5 is a graph schematically showing the change in the RRI acquisition rate with respect to vibration. The ARC in the figure shows the change in the standard acquisition rate when the sensor electrodes 20L and 20R are not deteriorated. Generally, the acquisition rate of RRI decreases as the vibration generated in the vehicle increases. Similarly, when the vehicle speed or the acceleration in the front-rear direction of the vehicle increases, the acquisition rate of RRI decreases.

When the sensor electrodes 20L and 20R deteriorate, the value of the RRI acquisition rate according to the vibration generated in the vehicle and the vehicle speed decreases according to the degree of deterioration. That is, by comparing the RRI acquisition rate when the electrode is not deteriorated with the actual RRI acquisition rate based on the vibration and vehicle speed currently occurring in the vehicle, it is determined how much the electrode is deteriorated. can do.

For example, when a small deterioration occurs, the RRI acquisition rate for vibration is located in the shaded area shown as "deterioration: small" in FIG. Further, when moderate deterioration occurs, the RRI acquisition rate for vibration is located in the shaded area shown as "deterioration: medium" in FIG. Further, when a large deterioration occurs, the RRI acquisition rate for vibration is located in the shaded area shown as "deterioration: large" in FIG.

The electrode state determination unit 306 determines the degree of deterioration of each of the first electrode and the second electrode of the sensor electrodes 20L and 20R. Then, the electrode state determination unit 306 supplies a signal indicating the determination result (hereinafter, referred to as an electrode deterioration determination signal DJS) to the control unit 400.

Referring to FIG. 4 again, the electrode function switching circuit 307 switches the electrode functions of the first electrodes 20LA and 20LB of the sensor electrode 20L. Further, the electrode function switching circuit 307 switches the electrode functions of the first electrodes 20RA and 20RB of the sensor electrode 20R.

The electrode function switching circuit 307 is the first electrode and the first electrode of each of the sensor electrodes 20L and 20R based on various information read from the memory 303 by the control unit 400 and the gripping signal GS detected by the gripping signal detection circuit 302. 2 The function of the electrode is switched for the electrode.

Further, the electrode function switching circuit 307 switches the electrode functions of the first and second electrodes of the sensor electrodes 20L and 20R based on the electrode deterioration determination signal DJS generated by the electrode state determination unit 306. .. Specifically, the electrode function switching circuit 307 is relative when the deterioration degree of at least one of the first electrode and the second electrode is a predetermined degree or more (for example, “deterioration degree: medium” or more shown in FIG. 5). The electrode functions are switched (set) so that the electrode with a large degree of deterioration is a neutral electrode and the electrode with a relatively small degree of deterioration is an active electrode. For example, in the electrode function switching circuit 307, when the degree of deterioration of the second electrode 20LB of the sensor electrode 20L is equal to or higher than a predetermined value and the degree of deterioration is relatively larger than that of the first electrode 20LA, the first electrode 20LA is the active electrode and the first electrode 20LA. The electrode function is switched so that the two electrodes 20LB become the neutral electrode.

The control unit 400 controls each unit of the biological information detection unit 30. In particular, the control unit 400 controls the electrode function switching circuit 307 to switch the electrode functions of the first and second electrodes of the sensor electrodes 20L and 20R, respectively.

The operation of the control unit 400 and the electrode function switching circuit 307 will be described in detail below.

FIG. 6 is a flowchart showing a processing routine of the electrode function switching process.

First, the control unit 400 accesses the memory 303 and acquires registration information about the type of vehicle (STEP 101). Further, the control unit 400 reads out the setting information about the setting of the function of each sensor electrode from the memory 303 (STEP 102).

The control unit 400 determines whether or not the setting of the electrode function (that is, the initial setting) to be set as the initial state is the first mode based on the registration information and the setting information read from the memory 303 (STEP 103). For example, when the type of vehicle in the registration information indicates a large vehicle such as a truck, in such a vehicle, the steering wheel is installed on a relatively horizontal surface of revolution, so that the driver has a hand on the front side of the steering wheel. There will be more opportunities to drive with the steering wheel. Therefore, by setting the second mode, it is possible to increase the chances of acquiring biometric information. That is, it may be determined whether the initial setting is the first mode or the second mode according to the type of the vehicle on which the biological information acquisition system 100 is mounted.

When it is determined that the initial setting is the first mode (STEP 103: YES), the control unit 400 determines whether or not the grip signal GS is detected by the grip signal detection circuit 302 (STEP 104). On the other hand, if it is determined that the initial setting is not the first mode (STEP103: NO), the process proceeds to STEP106.

When it is determined in STEP 104 that the gripping signal is detected (STEP 104: YES), the control unit 400 controls the electrode function switching circuit 307, and the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively, according to the setting of the first mode. The electrode is set to an active electrode or a neutral electrode (STEP105).

On the other hand, when it is determined in STEP104 that the gripping signal is not detected (STEP104: NO) and when it is determined in STEP103 that the setting is not the first mode (STEP103: NO), the control unit 400 sets the electrode function switching circuit 307. It is controlled so that the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively, are set to the active electrode or the neutral electrode according to the setting of the second mode (STEP106). If it is determined that the gripping signal is not detected, if the second mode is set, the bioelectric signal BS is activated from the driver's hand placed in front of the steering wheel even when the steering wheel is not gripped. By acquiring with electrodes, the chances of detecting biological information can be increased.

After executing STEP 105 and STEP 106, the process proceeds to the next STEP shown as "A" in FIG.

FIG. 7 is a flowchart showing a processing routine of electrode function switching processing after STEP 105 and 106.

The control unit 400 acquires vehicle acceleration information and vehicle speed information via the transmission / reception circuit 304 (STEP201).

The control unit 400 determines the traveling state of the vehicle based on the acquired acceleration information and vehicle speed information (STEP202). For example, the control unit 400 determines the magnitude of vibration generated in the vehicle and the acceleration in the front-rear direction based on the acceleration information.

The control unit 400 determines whether or not the magnitude of the vibration generated in the vehicle and the vehicle speed are each predetermined or higher (STEP 203).

When it is determined that at least one of the magnitude of the vibration generated in the vehicle or the vehicle speed is equal to or higher than a predetermined value (STEP203: YES), the control unit 400 controls the electrode function switching circuit 307 to switch to the currently set mode. Regardless of the setting of the second mode, the first electrode 20LA of the sensor electrode 20L and the first electrode 20RA of the sensor electrode 20R are set as the active electrodes, and the second electrode 20LB of the sensor electrode 20L and the second electrode 20RB of the sensor electrode 20R are set. Is set to the neutral electrode (STEP204).

On the other hand, when it is determined that both the magnitude of the vibration generated in the vehicle and the vehicle speed are less than a predetermined value (STEP 203: NO), the control unit 400 maintains the currently set mode (STEP 205).

The biometric information detection circuit 301 generates a biometric information signal BIS based on the bioelectric signal BS acquired from the sensor electrodes 20L and 20R in the state of the electrode function set in STEP204 or STEP205. The control unit 400 acquires the biometric information signal BIS from the biometric information detection circuit 301 (STEP206).

The RRI calculation unit 305 calculates RRI based on the biological information signal BIS (STEP207). The RRI calculation unit 305 supplies RRI data indicating the calculated RRI to the electrode state determination unit 306.

The electrode state determination unit 306 has a sensor electrode 20L (first electrode 20LA, second electrode 20LB) and a sensor electrode 20R (first electrode 20RA) based on the RRI data supplied from the RRI calculation unit 305 and acceleration information or velocity information. , The second electrode 20RB) is determined whether or not each of them is deteriorated (that is, whether or not the degree of deterioration is equal to or higher than a predetermined value) (STEP 208).

When it is determined that either the first electrode or the second electrode of each sensor electrode is deteriorated (STEP 208: YES), the electrode state determination unit 306 controls the electrode deterioration determination signal DJS indicating the degree of deterioration of the electrodes. Supply to. The control unit 400 receives the electrode deterioration determination signal DJS, and supplies an electrode deterioration notification request to the transmission / reception circuit 304 accordingly. The transmission / reception circuit 304 wirelessly transmits the electrode deterioration notification request to the display device 40. The display device 40 receives the electrode deterioration notification request and displays a text message notifying the electrode deterioration on the display screen in response to the request (STEP 209).

Further, the control unit 400 controls the electrode function switching circuit 307 according to the electrode deterioration determination signal DJS, and causes the electrode function to be switched (STEP210). For example, in a state where the first electrode is active and the second electrode is set to neutral, the degree of deterioration of the first electrode is equal to or higher than a predetermined value, and the degree of deterioration is relatively larger than that of the second electrode. When the determination signal DJS is supplied, the electrode function switching circuit 307 switches the electrode function so that the first electrode is the neutral electrode and the second electrode is the active electrode.

On the other hand, when it is determined in STEP 208 that the electrodes have not deteriorated (STEP 208: NO), the electrode state determination unit 306 supplies the electrode deterioration determination signal DJS indicating that none of the electrodes has deteriorated to the control unit 400. The control unit 400 receives the electrode deterioration determination signal DJS, and in response to this, maintains the state of the previous electrode functions of the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively.

The control unit 400 may execute all the steps of the process routine of the electrode function switching process shown in FIGS. 6 and 7, or may omit some steps.

By the above processing steps, the operation of the electrode function switching processing is performed.

In the biometric information acquisition system 100 of this embodiment, the first electrodes (20LA and 20RA) of the sensor electrodes 20L and 20R are neutral electrodes, and the second electrodes (20LB and 20RB) of the sensor electrodes 20L and 20R are active electrodes. In principle, the state set to is set to. In this way, by using the second electrode, which has a relatively small rubber electrode wear because the fingertips come into contact, as the active electrode, instead of the first electrode, which has a large wear of the rubber electrode because the driver's palm comes into contact, the sensor electrode. Can extend the life of the.

Further, the biological information acquisition system 100 of this embodiment is configured to be able to switch the functions of the first electrode and the second electrode according to the driving condition of the vehicle. For example, when the driver is not holding the steering wheel and is operating with his / her hand on the steering wheel, the electrode function is such that the first electrode becomes the active electrode and the second electrode becomes the neutral electrode. By switching the above, it becomes possible to acquire the biometric information signal BIS. In addition, even in situations where it is difficult to grip the steering wheel with both hands, such as when there is large vibration in the vehicle, the electrode function is switched so that the first electrode becomes the active electrode and the second electrode becomes the neutral electrode. By doing so, the biological information signal BIS can be acquired.

Further, in the biometric information acquisition system 100 of this embodiment, the RRI is calculated based on the biometric information signal BIS, and the deterioration of the sensor electrodes 20L and 20R (that is, each electrode) is calculated based on the calculated RRI data and the acceleration information or the vehicle speed information. The wear of the rubber electrodes constituting the above) is determined. By notifying the driver of the deterioration of the sensor electrode based on the determination result and encouraging repair or replacement, the biometric information signal BIS can always be maintained in a stable state. Further, by switching the functions of the first electrode and the second electrode respectively according to the deterioration of the sensor electrodes 20L and 20R, it is possible to acquire the biometric information signal BIS with the non-deteriorated electrode as the active electrode. Become.

Further, in the biological information acquisition system 100 of this embodiment, a plurality of hole HLs are formed on the surfaces of the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively. Therefore, the driver's hand is less likely to slip as compared with the case where such a hole is not formed. Therefore, the handle can be smoothly operated even when the handle is gripped via the rubber electrode. Further, when the handle cover 10 is sewn or attached to the handle, the rubber electrode is stretched and cracks may occur, which may deteriorate the performance of the rubber electrode. By providing the rubber electrode, it is possible to increase the elasticity of the rubber electrode and suppress the deterioration of the performance of the rubber electrode.

The present invention is not limited to that shown in the above examples. For example, in the above embodiment, a plurality of hole HLs are formed on the surfaces of the first electrode and the second electrode of the sensor electrodes 20L and 20R, respectively, and these are ring-shaped circles of the base material portion constituting the handle cover 10. The case where they are arranged along the circumferential direction has been described as an example. However, the arrangement of the holes is not limited to this, and for example, holes may be randomly formed on the surfaces of the first electrode and the second electrode. Further, each of the first electrode and the second electrode may be formed in a mesh shape. Further, a plurality of holes may be formed in one of the first electrode and the second electrode (that is, only the first electrode or only the second electrode). Further, although the shape of the hole HL is circular in FIGS. 2A and 2B, it may have an elliptical shape, a rectangular shape, or a polygonal shape.

Further, in the above embodiment, the case where the electrode function is switched (set) based on the detection result of the gripping signal, the magnitude of the vibration generated in the vehicle, etc. has been described as an example, but the trigger for switching the electrode function is The present invention is not limited to this, and it may be configured so that the electrode function can be switched according to the driving condition of the vehicle.

Further, in the above embodiment, the biometric information acquisition system 100 includes a biometric information detection unit, a handle cover mounted on the steering wheel of the vehicle, and sensor electrodes formed on the surface of the base material portion of the handle cover. This is explained as an example. However, instead of the form of such a steering wheel cover, the biometric information detection unit and the sensor electrode may be integrally formed with the steering wheel of the vehicle.
Further, in the above embodiment, the sensor electrodes 20L and 20R have been described as rubber electrodes, but the present invention is not limited to this, and other materials such as, for example, applying a conductive paint to the surface of the handle cover or the base material portion of the handle. May form a sensor electrode.

100 Biometric information acquisition system 10 Handle cover 20L, 20R Sensor electrode 20LA, 20RA 1st electrode 20LB, 20RB 2nd electrode 30 Biometric information detection unit 40 Display device 300 Power supply circuit 301 Biometric information detection circuit 302 Gripping signal detection circuit 303 Memory 304 Transmission / reception Circuit 305 RRI calculation unit 306 Electrode state determination unit 307 Electrode function switching circuit 400 Control unit

Claims (6)

The base material that is installed on the handle of the moving object,
A first electrode provided on the base material portion and arranged at a position on the front side when viewed from the driver side for gripping the handle.
A second electrode provided on the base material portion and arranged at a position on the back side when viewed from the driver side for gripping the handle, and a second electrode.
A biometric information detection unit that detects biometric information of a driver holding the steering wheel via at least one of the first electrode or the second electrode.
Have,
The biological information detection unit is a biological information detection device, characterized in that the functions related to the detection of the biological information of the first electrode and the second electrode are switched according to a situation related to the detection of the biological information. The biometric information detection unit acquires the biometric information by using the first electrode as a neutral electrode for imparting a reference potential to the driver and the second electrode as an active electrode for acquiring the biometric signal of the driver. The first aspect of using the first electrode as the active electrode and the second electrode as the neutral electrode to acquire the biometric information is described in a situation related to the detection of the biometric information. The biometric information detection device according to claim 1, wherein the biological information is switched accordingly. 2. The situation related to the detection of biological information includes a state in which the driver grips the handle, a state in which the first electrode and the second electrode are deteriorated, or a state in which the moving body travels. The biological information detection device according to the above. The biological information detection unit acquires information on the degree of deterioration of the first electrode and the second electrode, and the electrode having a relatively large degree of deterioration among the first electrode and the second electrode is used as the neutral electrode. The biometric information detection device according to claim 3, wherein an electrode having a relatively small degree of deterioration is set as the active electrode. It is characterized by having an output unit that determines whether or not the first electrode or the second electrode is deteriorated based on the information acquired from the first electrode and the second electrode and outputs the determination result. The biometric information detection device according to any one of claims 1 to 4. The living body according to any one of claims 1 to 5, wherein each of the first electrode and the second electrode has a plurality of pores arranged along the stretching direction of the base material portion. Information detector.

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